Week 3

Question 1

What is the general distrubution of number of parasites species per host species?

Answer 1

Fewer parasite species the greater the parasite frequency

Question 2

What is the parasite load across a population?

Answer 2

Frequently over-dispersed
This mean that some are heavily infected while others are uninfected

Question 3

Why is the variation across a population of interest?

Answer 3

This principle is the interest of ecological immunity

Question 4

What was discovered about malaria infections in Kenyan children?

Answer 4

Children living in the 10% of most malarious house had twice as many malaria infections as those in the 10% least malarious houses

Question 5

What was caused the difference in malaria infections amogst Kenyan children?

Answer 5

Genetics and household

Question 6

What factors can impact the variarion of infection levels?

Answer 6

Sex
Age
Geographic region
Social status
Food availability and nutrition
Condition (Stress)
Environmental conditions

Question 7

How does temperature impact the virulence in the bacterial parasite Pasteuria ramose infecting daphnia?

Answer 7

In warmer conditions the Daphnia become sterilized
In colder conditions the infection is benign

Question 8

What factors can impact immunity?

Answer 8

Temperature
Condition (stress)
Age
Sex
Social position
Geographic region

Question 9

What is the drawback to Lymnaea stagnalis withdrawing into its shell in response to a predator?

Answer 9

Withdrawing in the shell causes reduced number of hemocytes that are capable of phagocytosis

Question 10

How did the scientist discover the trade off with Lymnaea stagnalis withdrawing into its shell and loss of hemocytes?

Answer 10

Compared phagocyosis to total volume blood in both clean and dirty water.
Clean water snails only slightly declined
Dirty water snails declined dramatically, strated higher than clean water snails and ended lower than clean water snails

Question 11

What are the 2 main groups of costs to immunity?

Answer 11

Evolution and maintenance
Deployment

Question 12

What is the car house paradox?

Answer 12

You have finite money so do you spend money on a nice house or a nice car

Question 13

How does the car house paradox relate to genetic traits?

Answer 13

There is only a limited amount of resources so organisms has to make a choice (though they can’t choose) between which trait to invest in and evolved

Question 14

What is more commanly seen with both the car house paradox and the genetic variance?

Answer 14

That a person or an organism will more often invest in a medium between the two i.e nice car and nice house but not as nice is buying only 1

Question 15

What happens to the difference in allocation between trait A and trait B in high variation in acquisition?

Answer 15

Low variation in allocation

Question 16

What happens to the difference in allocation between trait A and trait B in low variation in acquisition?

Answer 16

High variation in allocation

Question 17

How can an immune defense impact reproduction as found Drosophila in different yeast environments?

Answer 17

In low yeast environments there is a negative correlation between resistance and fecundity
In ‘unlimited’ yeast environements there is a slight positive correlation in resistance and fecundity

Question 18

How does seasons impact immune functions?

Answer 18

Evidence reports a lot of seasonal variation in birds and mammals with potentially winter decreasing function due to low resources

Question 19

What can limit immune systems in low ambient temperatures?

Answer 19

Low ambient temperature are stressors for increased corticosteroids which over long periods decrease actvity

Question 20

What are the 2 hypothesis that cause winter immune enhancements?

Answer 20

H 1 - immune inhancement is the result of active upregulation of immune activity to counteract winter supressions
H 2 - immune activity is traded off during specific life phases e.g reduction in investment in reproduction due to both reproduction adn immunity carrying heavy costs

Question 21

How does lifestyle impact bumblebee immune response?

Answer 21

Non-foraging groups are better at encapsulation, due to not spending resources foraging

Question 22

How does colony size impact immune reponse?

Answer 22

Smaller colonies spend more time foraging so have a reduction in encapsulation

Question 23

What happens when drosophilia were selectively breed by scientists to be heavily specialised for encapsilation?

Answer 23

At higher resource levels both wildtype and highly encapsulated drosophilia have equal ability to compete for larval food.
At lower resource levels wildtypes outcompete the highly encapsulated showing a cost to encapsualtion

Question 24

What does tolerance represent on a graph?

Answer 24

Tolerance can be linear or sigmoidal

Question 25

What are 4 ways that can tolerance and resistance interact with 2 genotypes (A and B)

Answer 25

1 - Both A and B can resist parasite well with resistance better at preventing and tolerance better at maintaining
2 - A is better at tolerating than B is at resisisting so as parasites increase the worse B does
3 - A is better at resisting than B so at lower levels host fitness is better but at higher parasite levels B has a higher host fitness
4 - Either A or B has a higher virulence than the other but both have an equal amount of resistance and tolerance